The
AVS-VCO-1
Voltage
Controlled
Oscillator
User Guide
Waveform Diagrams
Page 3 of 4
www.AvonSynth.com
Waveform
Bias
Initial
Frequency
Pitch
Tracking
Waveform
Shape
0v
Triangle Output
+5v
-5v
0v
Sine Output
+5v
-5v
0v
Square Output
+5v
-5v
Sawtooth Output
0v
+5v
-5v
Your new AVS-VCO-1 Voltage Controlled Oscillator was expertly
calibrated by hand for great 1v-per-octave tracking over a large
frequency range. However, over time it is possible that the
calibration could drift, or accidental movement of the calibration
trimmers could decrease the precision of the tracking. Multiturn
trimmer potentiometers are used in this module for increased
accuracy in calibration and can be turned using a small
fl
at-head
screwdriver or other suitable implement.
The Bias trimmer centers the Sawtooth wave symmetrically around ground.
Since all of the outputs are derived from the sawtooth core of the oscillator,
this a
ff
ects the output of all waves and the Bias trimmer should be set
fi
rst when calibrating. The Waveform Shape trimmer adjusts the symmetry
of the triangle waveform, and since the sine wave is derived from the
triangle wave, this also doubles as an adjustment of the shape of the sine.
The Freq Init (Initial Frequency) trimpot is used to set the
frequency range of the Pitch knob. This is generally set so that
at the pitch knob's minimum value, the output frequency is just
below the audible range. The 1v/Oct trimmer is responsible for
setting the shape of the exponential relationship between the
input CVs and the oscillator's output frequency. Calibration is
carried out by monitoring an output, and feeding the 1v/Oct
input precise control voltages in 1v increments. Adjust this
trimmer until each 1v increment results in a doubling of the
frequency of the output signal.
Recalibrating this module requires the use of accurate
multimeters, frequency counters, and precise control voltage
generators. If you are not able to carry out recalibration yourself,
the engineers at AvonSynth will be happy to recalibrate your
module for you free of charge during the warranty period.
Calibration Trimpots
Waveform Diagrams
Calibration Trimpots
